Cyanotic newborn and critical congenital heart disease screening — formative SAQs

SAQ 1 (10)

A term infant born after an uncomplicated pregnancy is noted on the postnatal ward at thirty hours of age to be dusky during a feed but otherwise comfortable, with no respiratory distress. The midwife records a pulse oximetry of 86 per cent in the right hand and 84 per cent in the foot in air. There is no murmur. [2] [3]

a) Interpret these pulse-oximetry findings against the screening thresholds, and state the immediate next step. (2 marks) [2]

b) The baby is alert and looks well. Justify why this appearance does not lower your concern, and name the bedside examination findings that would localise a cardiac lesion. (3 marks) [2]

c) Outline your immediate management, naming the drug, the dose and the airway consideration, and explain why it precedes the echocardiogram. (3 marks) [8] [9]

d) The team asks whether to give 100 per cent oxygen while awaiting the team. Explain the principle that governs oxygen use in a suspected duct-dependent mixing lesion. (2 marks) [2]

SAQ 2 (10)

A two-day-old infant is brought to the emergency department grey, mottled and tachypnoeic, with weak femoral pulses and a capillary refill of five seconds. The blood gas shows a pH of 7.10 with a lactate of 8 mmol per litre. The baby was discharged home well at twenty-four hours and had no antenatally detected anomaly. [1] [8]

a) Give a problem representation and state the most likely physiological category of lesion, with your reasoning. (2 marks) [2]

b) Outline the resuscitation in order, naming the specific infusion that reopens the duct, its starting dose range, and the monitoring required. (3 marks) [9] [8]

c) Discuss the differential diagnosis of neonatal cyanosis and the role of the hyperoxia test and the echocardiogram in resolving it, including the limits of the hyperoxia test. (3 marks) [2]

d) Explain why this presentation represents a failure of the screening programme, and state the layered screening that should have detected the lesion earlier. (2 marks) [1]